Re: .dsk file format

[Rubywand <rubywand@swbell.net>]

Benjamin Fry writes ...
> 
> hi all,
> 
> i'm curious to find out more about byte-level (or i guess nybble, in this
> case) format used for apple II discs. essentially, if i'm looking for the
> doc that would allow me to write a util that can CAT a .dsk image, or pull
> individual files from the .dsk. could someone point me in the correct
> direction on where i might find such a thing?
> 
 ....

     The format of a standard 5.25" .dsk disk image file is pretty simple. It
includes only the data from a standard 35-track, 16-sector disk. It does not
include any Address Header, etc. info which is embedded in a diskette as part
of the formatting process.

     Usually, data in a .dsk file will be in the same order as used by DOS 3.3.
So, for example, the first 256-byte block of bytes in a .dsk file will
correspond to Track 0/Sector 0. The 16th 256-byte block will correspond to
Track 0/Sector 15 (or, in hex notation: Track $00/Sector $0F).  The 17th
256-byte block will correspond to Track 1/Sector 0, ... etc..

     Besides the book mentioned by Matthew, you can find some DOS 3.3 info in
the Csa2 Apple II FAQs at http://home.swbell.net/rubywand/Csa2DOSMM.html .



Rubywand